Microwave unsweetened chocolate and butter in a large microwaveable bowl for 2 minutes or until butter is melted. Stir until chocolate is completely melted. Add sugar and mix well. Blend in eggs and vanilla. Stir in flour. Refrigerate 1 hour. Shape into 1 inch balls and place on lightly greased baking sheets. Bake 9 minutes at 350 degrees. Let it stand 1 minute on baking sheet. Transfer to wire rack. While still warm place unwrapped peppermint kiss in center and push down until set in cookie. Let kiss cool completely before transfering….they will melt and become a puddle if touched before cooled again. Makes about 5 dozen.